Adjustable air shutter for a gas burner

ABSTRACT

A gas mixing valve includes a conduit, a shutter, and an elongated flexible adjustment member. The conduit is coupled between a gas supply and a gas burner and includes an opening. The shutter is positioned adjacent to the conduit and is movable between a plurality of positions relative to the conduit opening to adjust a flow of air into the conduit. The elongated flexible adjustment member is coupled to the shutter and configured to move the shutter between the plurality of positions.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention generally relates to gas fireplaces, and more particularly relates to structures for adjusting an air and gas mixture for a fireplace burner.

2. Related Art

Gas fireplaces typically include a gas burner positioned within a combustion chamber of the fireplace. The gas burner is coupled via a gas conduit to a gas valve typically positioned outside of the combustion chamber but within an outer enclosure of the fireplace. A separate gas mixing valve is positioned between the conduit valve and is adjustable to provide a flow of fresh air into the flow of gas in the conduit to provide a desired air and gas mixture to the gas burner. Most gas mixing valves are configured for adjustment to a setting at the time of installing the fireplace or gas burner. However, it can be time consuming to obtain the proper adjustment of the gas mixing valve to accommodate for considerations such as fuel type and altitude. This is because the valve in some gas fireplaces is sealed below the combustion chamber, not allowing easy access to the valve for adjustment. In order to adjust the valve for these fireplaces, the installer or owner must remove portions of the fireplace to gain access to the valve.

Some solutions to the above presented problem are presented in U.S. Pat. No. 5,553,603 to Barudi and U.S. Pat. No. 5,931,661 to Kingery. In each of the patents, an adjustable member is movable relative to an opening in a gas conduit that provides a gas flow to a gas burner. Barudi discloses an air shutter that is disposed around the gas conduit and moved within a multi-piece adjustment mechanism. A shutter arm is coupled to air shutter and rotates the air shutter between positions covering and removed from an opening in the conduit. An actuator arm is coupled to the shutter arm at one end and extends to a positioned spaced apart from the conduit at an opposing end of the actuator arm. The opposing end of the actuator arm may be positioned for easier access than the air shutter, but is still not easily accessible because it is located at the bottom of the combustion chamber. Also, with multiple parts and connections of those parts, the Barudi adjustment mechanism maybe subject to greater mechanical failure.

Kingery discloses a channel shaped shutter that is linearly slideable over a window formed in the gas conduit. A shaft is coupled to the shutter at a first end of the shaft while a second, threaded end of the shaft extends to position spaced apart from the conduit on an opposing side of a sealed panel. By rotating a nut on the threaded end of the shaft, the shutter moves linearly relative to the opening to adjust an air and gas mixture in the conduit, but is still positioned below the combustion chamber. Again, the person adjusting the shutter must do so from the inconvenient location under the fireplace.

These and other known gas mixing valves have limitations that restrict the easy of adjusting the air and gas mixture for the fireplace burner.

SUMMARY OF THE INVENTION

The present invention relates to structures for adjusting an air and gas mixture for a fireplace burner. One aspect of the invention relates to a gas mixing valve that includes a conduit, a shutter, and an elongated flexible adjustment member. The conduit is coupled between a gas supply and a gas burner and includes an opening for the flow of air into the conduit. The shutter is positioned adjacent to the conduit and is movable between a plurality of positions relative to the conduit opening to adjust the flow of air into the conduit. The elongated flexible adjustment member is coupled to the shutter and configured to move the shutter between the plurality of positions.

Another aspect of the invention relates to a fireplace that includes an outer enclosure, a combustion chamber enclosure positioned within the outer enclosure and defining a combustion chamber, a gas burner positioned within the combustion chamber, and a gas mixing valve. The gas mixing valve is configured to control an air and gas mixture provided to the gas burner. The gas mixing valve includes a conduit coupled between the gas burner and a fuel source, a shutter, and an adjustable member. The conduit includes an opening and the conduit is positioned within the outer enclosure. The shutter is adjustable relative to the conduit opening and is also positioned within the outer enclosure. The adjustment member is coupled to the shutter at a first end and extends at a second end to a location accessible from outside of the outer enclosure. A shape of the adjustment member is adjustable to position the second end at any of a plurality of positions relative to the conduit. The adjustment member adjusts the shutter with a push/pull force applied to the second end.

A further aspect of the invention relates to a method of adjusting an air and gas mixture in a gas fireplace. The fireplace includes an outer enclosure and a combustion chamber. The method includes providing a gas mixing valve that includes a conduit having an opening formed in a sidewall thereof, a shutter, and an elongate flexible adjustment member, the conduit carrying a flow of gas. The method also includes positioning the conduit and the shutter within the outer enclosure, securing a first end of the adjustment member to the shutter and positioning a second end of the adjustment member remotely from the shutter, and applying an axially force to the second end of the adjustment member. The adjustment member is configured to translate the axially force to the shutter to move the shutter between a plurality of positions relative to the conduit opening to adjust an air flow into the conduit.

The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. In particular, the example embodiments described below in relation to the Figures are the application of the present invention in a fireplace, whereas many other fields may be applicable to fulfill the purposes and intents of the present invention. Figures in the detailed description that follow more particularly exemplify certain embodiments of the invention. While certain embodiments will be illustrated and describe embodiments of the invention, the invention is not limited to use in such embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of an example gas mixing valve assembly having a shutter member in a closed position;

FIG. 2 is a top view of the gas mixing valve assembly shown in FIG. 1;

FIG. 3 is an exploded perspective view of the gas mixing valve assembly shown in FIG. 1;

FIG. 4 is a perspective view of the gas mixing valve assembly shown in FIG. 1 with the shutter member in a partially open position;

FIG. 5 is a top view of the gas mixing valve assembly shown in FIG. 3;

FIG. 6 is a perspective view of the gas mixing valve assembly shown in FIG. 1 with the shutter member in a fully open position;

FIG. 7 is a top view of the gas mixing valve assembly shown in FIG. 5;

FIG. 8 is a perspective view of a fireplace that includes an example gas mixing valve assembly according to principles of the present invention;

FIG. 9 is a front view of the fireplace shown in FIG. 8;

FIG. 10 is a perspective view of the fireplace shown in FIG. 8 with some of the fireplace panels removed to more clearly show the gas mixing valve assembly;

FIG. 11 is a front view of the fireplace shown in FIG. 10;

FIG. 12 is a top view of the fireplace shown in FIG. 10; and

FIG. 13 is a flow chart illustrating steps of an example method of adjusting an air and gas mixture in a gas fireplace.

While the invention is amenable to various modifications and alternate forms, specifics thereof have been shown by way of example and the drawings, and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to structures for adjusting an air and gas mixture for a fireplace burner. The present invention is especially useful for providing adjustment of the air and gas mixture using a more convenient, easy to access way for an operator of the fireplace. One aspect of the invention relates to a gas mixing valve that is adjustable to modify the air and gas mixture. The gas mixing valve includes a conduit, a shutter, and an elongated flexible adjustment member. Regardless of a position of the conduit and shutter relative to the fireplace combustion chamber or the gas burner positioned in the combustion chamber, the adjustment member can be arranged to provide improved accessibility for the operator. The conduit is coupled between a gas supply and a gas burner and includes an opening for the flow of air into the conduit. The shutter is positioned adjacent to the conduit and is movable between a plurality of positions relative to the conduit opening to adjust the flow of air into the conduit. The adjustment member is coupled to the shutter and configured to move the shutter between the plurality of positions.

FIGS. 1-7 illustrate an example gas mixing valve assembly 10. The gas mixing valve assembly 10 includes a conduit 12, a shutter 14, and an adjustment member 16 that moves the shutter 14 relative to an opening 18 (see FIG. 3) in an end of the conduit 12. The conduit 12 may be coupled to a gas burner to provide a supply of gas and/or a mixture of gas and air to the gas burner. The opening 18 may include first and second notches 19, 21 (see FIGS. 3-7) formed in a sidewall of the conduit 12. The opening 18 including notches 19, 21 may have any desired size and shape.

The shutter 14 preferably has an inner diameter that is substantially the same size as an outer diameter of the conduit 12 to improve control of air flow into the opening 18. The shutter 14 is movable in an axial direction; that is, a direction parallel to a longitudinal axis of the conduit 12. The shutter 14 preferably has a length (measured in an axial direction of the conduit 12) and an overall configuration that enable the shutter to extend well beyond the end of the conduit 12 past the opening 18. FIGS. 1 and 2 illustrate the shutter 14 extending beyond the end of the conduit 12 and into contact with an adjustment member bracket 28 to substantially encapsulate the opening 18 and a gas orifice or nozzle 38 that directs a flow of gas into the conduit 12. In some embodiments (not shown) two or more separate shutters are provided to help control the flow of air into conduit.

The conduit 12 is shown in FIGS. 1-7 having a cylindrical shape and a generally circular cross-section. In other embodiments, the conduit 12 may have different cross-sectional shapes. Regardless of the cross-sectional shape, size or features of the conduit 12, the shutter 14 is preferably configured to at least partially cover an air flow opening into the conduit. For example, the shutter may have a box-shaped design with planar walls that substantially cover an opening in a sidewall of a conduit having a circular cross-section, as shown and described in U.S. Pat. No. 5,931,661, which patent is incorporated herein by reference. U.S. Pat. No. 5,931,661 also discloses movement of the shutter in a direction substantially perpendicular to the longitudinal axis of the conduit. Such a configuration and movement of the shutter relative to an opening in the conduit may be possible or enhances using features of the example embodiments described herein.

The adjustment member 16 includes a first end 20 that is coupled to the shutter 14, and a second end 22 that has coupled to it a knob 24 and a knob base 26. The adjustment member 16 includes a coaxial structure in which a sleeve or tube shaped member 27 houses a wire or cable member 25. The wire 25 slides and moves within the sleeve 27 while the sleeve 27 maintains a fixed position and supports the wire. One end of the sleeve 27 engages the adjustment member bracket 28 that is positioned adjacent to an end of the conduit 12 next to the opening 18. The knob base 26 is coupled to an opposing end of the sleeve 27. The knob base 26 may be mounted to a plate or other fixed structure to help maintain the fixed position of the sleeve 27 relative to the wire 25.

The knob 24 is coupled to the wire 25 at the second end 22. The knob 24 is movable in a closing direction C and an opening direction 0 (see FIGS. 1 and 2) to move the shutter 14 into various positions relative to the opening 18. FIGS. 4 and 5 and FIGS. 6 and 7 illustrate two different positions of the shutter 14 wherein the opening 18 is open different amounts for the flow A of different amounts of air into the conduit 12.

The wire 25 and sleeve 27 of the adjustable member 16 may be configured and function similar to a gear shifting cable used in, for example, bicycle applications wherein the cable extends from a handlebar of the bicycle (for easy access by the bicycle operator) to the gear assembly at the rear wheel of the bicycle. In such an application, moving the encapsulated wire relative to the outer sleeve provides shifting of the gear assembly. Such coaxial type cables are generally flexible in that they can be curved along the length of the cable to travel along a desired path (e.g., along the bicycle frame). Although such a coaxial cable has certain flexible characteristics that permit curving and bending of the cable, the encapsulated wire is able to move within the outer sleeve making it possible to translate an axial force along the length of the wire without the wire buckling or kinking. In other applications, a coaxial type cable may be replaced with a single wire member that is flexible or pliable along the length of the wire, but has an inherent axial stiffness that is useful for translating an axial force along the length of the wire. As applied to adjustable member 16, such a single wire may be applicable to or comparable to the wire 25 with the sleeve 27 removed. In order to prevent the wire 25 from buckling or kinking between the knob base 26 and the adjustment member bracket 28, the wire 25 may require a plurality of retaining members along its length to secure the wire 25 to another stationary structure such as to the gas supply line 36. Some example retaining members include adjustable straps and fasteners.

An adjustment member that is flexible, bendable or that can be adjusted or arranged in some way to have different shapes for extending over different paths between the first and second ends 20, 22 is particularly useful when the gas mixing valve assembly 10 is used in an application such as a fireplace. In a fireplace application, as well as in other applications, it is desirous to position the knob 24 at a location that is easily accessible by an operator of the gas mixing valve assembly 10. If the adjustment member 16 is flexible or can at least be shaped or curved in some way to travel around obstructions and across non-linear paths, the adjustment member 16 provides many options for positioning of the knob at a preferred location to enhance ease of operation of the valve assembly 10.

FIGS. 1-7 illustrate a support wall 32 that corresponds to, for example, a combustion chamber enclosure panel of a fireplace. The support wall 32 defines an opening 33 through which the adjustment member 16 and the gas supply line 36 extend. A cover plate 30 includes a first opening 31 for the gas supply line 36, and a plurality of holes 29 through which the adjustment member 16 can extend for optimum positioning relative to the adjustment member bracket 28 and the shutter 14. The cover plate 30 is positioned over the opening 33. Different cover plate configurations may provide a different sized opening 33 to accommodate different configurations of the conduit 12, shutter 14, and gas supply lines 36.

A supply line locking bracket 34 helps to position the gas supply line 36 relative to the support wall 32. A gas supply orifice or nozzle 38 is secured to an end of the gas supply line 36 and helps direct a gas flow G (see FIG. 6) from the gas conduit 36 into the conduit 12. By adjusting a position of the shutter 14 relative to the opening 18, an amount of air flow A (see FIGS. 6 and 7) that mixes with the gas flow G can be controlled to optimized the gas and air mixture GA for a given gas burner application. In the shutter position shown in FIGS. 6 and 7, air can enter the conduit through the opening 18 at a location closer to the conduit than a position of the gas orifice 38. In the shutter position (not shown) wherein the shutter extend beyond an end of the conduit but not into contact with the adjustment member bracket 28, air can enter the conduit through an open end of the shutter, which open end is positioned adjacent to the gas orifice.

The conduit 12 and shutter 14 may alone or in combination define a chamber for mixing gas and air. FIGS. 4 and 5 illustrate the shutter positioned relative to the conduit opening 18 so as to at least partially define a chamber or space within which gas from the gas orifice 38 and air flow A can mix to provide a gas and air mixture. FIGS. 6 and 7 illustrate the shutter positioned relative to the conduit opening 18 so that the shutter does not define any part of a chamber within which gas from the gas orifice 38 and air flow A are mixed. FIGS. 1 and 2 illustrate the shutter positioned such that very little if any air flow A can enter the conduit opening 18 so that the shutter 14 and conduit 12 define a chamber that is filled primarily with only a gas flow provided by gas orifice 38.

Referring now to FIGS. 8 and 9, an example fireplace 200 is shown including a gas mixing valve assembly 210 having the same or similar features as described above related to gas mixing valve assembly 10. The fireplace 200 includes an outer enclosure 201, a combustion chamber enclosure 202, a gas burner 203, a gas valve assembly 204, a plenum 205 defined between the outer enclosure 201 and the combustion chamber enclosure 202, and a vent assembly 206.

The outer enclosure 201 includes top and bottom panels 242, 244, first and second side panels 246, 248, front and rear panels 250, 252, a control box 260 having a control box cover 261, and a top opening 270 configured to accommodate the vent assembly 206. The outer enclosure 201 is shown having a rectangular box shape in the Figures, but may have alternative configurations and shaped in other embodiments.

The combustion chamber enclosure 202 includes top and bottom panels 272, 274, first and second side panels 276, 278, a rear panel 280, and a front panel 282 (defined by portions of the top, bottom and side panels 272, 274, 276, 278) that has been removed to provide better viewing of the features shown within the combustion chamber enclosure 202. The panels 272, 274, 276, 278, 280, 282 define a combustion chamber 290 wherein the gas burner 203 is positioned for combusting gas to create a flame and heat. The front panel 282 may define an opening that can be covered by a sheet of glass or other transparent or translucent material that provides viewing of the flame within the combustion chamber 290.

The fireplace 200 may include other panels (not shown) that may be used to cover openings between the front panel 250 of the outer enclosure 201 and the front panel 282 of the combustion chamber enclosure 202. One such opening is viewable in FIG. 8 and provides access to the gas valve assembly 204, which is positioned within the plenum 205 between the side panel 276 of the combustion chamber enclosure 202 and the side panel 246 of the outer enclosure 201 behind the front panel 250 of the outer enclosure 201. This opening also provides access to the control box 260. A cover 261 that is removed in FIGS. 10 and 11 to illustrate components mounted within the control box 260 covers the control box 260. This opening may be covered with a removable panel that is held in place with quick release fasteners or other structures that provide relatively quick and easy removal of the panel to gain access to a valve 294 of the gas valve assembly 204, an outlet plug 207 positioned within the control box 260, and a knob 224 of the gas mixing valve assembly 210 that is also positioned within the control box 260.

FIGS. 10 and 11 illustrate the fireplace 200 with the top panel 242 of the outer enclosure 201 and top panel 272 of the combustion chamber enclosure 202 removed along with a portion of the front panel 250 of the outer enclosure 201 to more clearly illustrate the position of the gas valve assembly 204 and components mounted within the control box 260. In some fireplace embodiments, a similar portion of the front panel 250 may be removable to provide access to adjustable features and other components positioned within the plenum 205. In many fireplace embodiments, the front panel 250 of the outer enclosure 201 is covered with a decorative structure such as brick, rock, or a decorative surround. Such decorative members would prohibit removal of a portion of the front panel. Thus, it may be more practical to provide a removable panel that is positioned between the front panel 250 and a front panel of the combustion chamber enclosure 202 to gain the desired access to the plenum than removing a portion of the front panel 250. In other embodiments, portions of the decorative structure may be removable to gain access to a removable portion of the front panel 250 to provide access to the plenum 205.

The gas mixing valve assembly 210 includes a conduit 212 that is coupled to the gas burner 203, a shutter 214, and an adjustment member 216. The conduit 212 includes an opening 218 at an end of the conduit, and the adjustment member 216 includes a first end 220 coupled to the shutter 214, a second end 222 coupled to the knob 224, and a knob base 226 that couples the adjustment member 216 to a panel of the control box 260. The gas mixing valve assembly 210 may also include an adjustment member bracket 228 that couples the first end 220 to the combustion chamber enclosure 202, and a cover plate 230 positioned over an opening (not shown) formed in the side panel 276 of the combustion chamber enclosure 202. The gas valve assembly 204 may include a gas supply line 236 that extends from the gas valve 294 to the conduit 212, and a gas supply orifice 238 positioned adjacent to the openings 218 at an end of the conduit 212.

FIGS. 8-12 illustrate the opening 218 of the conduit 212 and shutter 214 positioned within the combustion chamber enclosure 202. Further, the gas mixing valve assembly 210 extends horizontally through the side panel 276 of the combustion chamber enclosure 202 into the combustion chamber 290. In other embodiments, the opening 218 and shutter 214 may be positioned within the plenum 205 or in some other space outside of the combustion chamber 290. The gas mixing valve assembly 210 may extend into the combustion chamber 290 through the bottom panel 274, the second side panel 278, or rear panel 280. Further, the gas mixing valve assembly 210 may be arranged such that the conduit 212 extends in a vertical direction rather than the generally horizontal orientation illustrated in FIGS. 8-12.

FIGS. 8-12 illustrate the second end 222 of the adjustment member 216, including the knob 224, positioned within the control box 260 adjacent to the front panel 250 but still within the outer enclosure 201. In other embodiments, the knob 224 may be exposed through the front panel 250, through a panel that is positioned to cover the opening or space provided between the front panel 250 and the front panel 282 of the combustion chamber enclosure 202, or at any other location on or within the fireplace 200 to provide a desired accessibility for an operator of the fireplace 200. In other embodiments, the second end 222 and knob 224 may extend outside of the outer enclosure and be exposed adjacent to the fireplace 200, for example, on a surface of a wall or in a box mounting in a wall of a living structure within which the fireplace 200 is installed.

FIG. 13 illustrates the steps of an example method of adjusting an air and gas mixture in a gas fireplace. A first step of the method includes providing a gas mixing valve having a conduit with an opening formed in a side wall thereof, a shutter, and an elongated flexible adjustment member. The conduit is configured to carry a flow of gas. The method also includes positioning the conduit and the shutter within an outer enclosure of the fireplace and securing an end of the adjustment member remotely from the shutter. The method may also include applying an axial force to the second end of the adjustment member and translating the axial force along a length of the adjustment member to the shutter to move the shutter between a plurality of positions relative to the conduit opening to adjust an air flow into the conduit. A result of adjusting a position of the shutter is alteration of a gas and air mixture within the conduit. The gas and air mixture in the conduit may be fed to a gas burner of the fireplace for combustion into a flame.

The present invention should not be considered limited to the particular examples or materials described above, but rather should be understood to cover all aspects of the invention as fairly set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the instant specification. 

1. A gas mixing valve, comprising: a conduit coupled between a gas supply and a gas burner, the conduit including an opening at an end thereof; a shutter positioned adjacent to the conduit opening and movable between a plurality of positions relative to the conduit opening to adjust a flow of air into the conduit; and an elongated flexible adjustment member coupled to the shutter and configured to move the shutter between the plurality of positions.
 2. The gas mixing valve of claim 1, further comprising an elongate tube configured to house a portion of the flexible adjustment member.
 3. The gas mixing valve of claim 1, wherein the flexible adjustment member is a cable or a wire.
 4. The gas mixing valve of claim 3, wherein the flexible adjustment member is configured as a coaxial cable.
 5. The gas mixing valve of claim 1, wherein the shutter is movable in response to a force applied axially along a length of the adjustment member.
 6. The gas mixing valve of claim 1, wherein the shutter is movable in a direction parallel to a longitudinal axis of the conduit.
 7. The gas mixing valve of claim 1, wherein the shutter and conduit each include a hollow cylindrical shape, an internal diameter of the shutter being substantially equal to an outer diameter of the conduit.
 8. The gas mixing valve of claim 1, wherein the shutter includes a continuous circumferential surface along an axial length of the shutter.
 9. The gas mixing valve of claim 1, wherein the conduit opening includes at least one notch formed in the conduit sidewall, and the shutter is movable relative to the at least one notch and configured to simultaneously cover portions of the first and second notches.
 10. The gas mixing valve of claim 1, wherein the opening includes an open end of the conduit and is defined at least partially by an end surface of the conduit.
 11. The gas mixing valve of claim 1, further comprising an adjustment member bracket having a planar surface against which the shutter engages in one of the plurality of shutter positions to minimize air flow into the conduit opening.
 12. A fireplace, comprising: an outer enclosure; a combustion chamber enclosure positioned within the outer enclosure and defining a combustion chamber; a gas burner positioned within the combustion chamber; and a gas mixing valve configured to control an air and gas mixture provided to the gas burner, the gas mixing valve comprising: a conduit coupled between the gas burner and a fuel source, the conduit including an opening, the conduit being positioned within the outer enclosure; a shutter adjustable relative to the conduit opening, the shutter being positioned within the outer enclosure; and an adjustment member coupled to the shutter at a first end and extending at a second end to a location accessible from outside of the outer enclosure, a shape of the adjustment member being adjustable to position the second end at any of a plurality of positions relative to the conduit, wherein the adjustment member adjusts the shutter.
 13. The fireplace of claim 12, wherein the shutter is movable in a direction parallel to an axis of the conduit.
 14. The fireplace of claim 12, wherein the adjustment member comprises an elongated flexible member.
 15. The fireplace of claim 12, wherein the shutter is positioned within the combustion chamber.
 16. The fireplace of claim 12, wherein the gas mixing valve extends in a horizontal direction through a side panel of the combustion chamber enclosure.
 17. The fireplace of claim 12, wherein the outer enclosure defines a control box positioned between a side panel of the combustion chamber enclosure and a side panel of the outer enclosure, the control box being accessible through a front panel of the outer enclosure, and the second end of the adjustment member is positioned within the control box.
 18. The fireplace of claim 12, wherein the adjustment member is configured to pass an axial force along a length of the adjustment member to move the shutter.
 19. The fireplace of claim 12, further comprising a gas nozzle configured to direct gas into the conduit.
 20. The fireplace of claim 19, wherein the shutter is moveable into at least one position wherein the gas nozzle is at least partially positioned within the shutter and another position wherein the gas nozzle is not positioned within the shutter.
 21. The fireplace of claim 19, wherein the gas nozzle is positioned outside of the conduit.
 22. The fireplace of claim 12, wherein the shutter is movable from a position in which a portion of the shutter extends distally from the conduit to define a portion of the conduit open, to a position retracted over the conduit such that the shutter does not extend distally beyond the distal end of the conduit.
 23. A method of adjusting an air and gas mixture in a gas fireplace, the fireplace including an outer enclosure and a combustion chamber, the method comprising: providing a gas mixing valve, the gas mixing valve including a conduit having an opening formed in a sidewall thereof, a shutter, and an elongated flexible adjustment member, the conduit carrying a flow of gas; positioning the conduit and the shutter within the outer enclosure; securing a first end of the adjustment member to the shutter and positioning a second end of the adjustment member remotely from the shutter; and applying an axially force to the second end of the adjustment member, the adjustment member being configured to translate the axially force to the shutter to move the shutter between a plurality of positions relative to the conduit opening to adjust an air flow into the conduit.
 24. The method of claim 23, further comprising positioning the second end at a location accessible at a front panel of the outer enclosure.
 25. The method of claim 23, wherein the shutter moves in a direction parallel to a longitudinal axis of the conduit.
 26. The method of claim 23, wherein the conduit includes first and second openings, and the shutter is configured and arranged to simultaneously cover portions of the first and second openings. 